Title of Invention

COATED THREAD

Abstract

The invention relates to a self locking thread meant for starching specially designed to attach buttons to fabric in clothes having a very high locking strength and a process by which stitching thread is impregnated and surface coated by a specially engineered fusible compound which Is applied under chosen conditions of stretch, humidity and temperature which can be subsequently thermally activated to impart self locking characteristics to the thread. The process has been particularly designed to ensure that properties like shade retention, smooth surface characteristics and low friction index are optimised. The process also creates a fusible matrices which when thermally activated causes the fibrillated structure of the stitching thread to exhibit increased cohesion.

Full Text

Field of the Invention The present invention relates to a coated self locking thread having an enhanced button security when stiched to clothes. The thread has a very high iocking strength. The thread is impregnated and surface coated with a special fusible compound capable of being activated by radiation heating, imparting superior strength, high tenacity, protecting the inner core from damage due to needle heat, ensuring excelient sewability and its resistance to abrasion. The thread produced are of a very high quality having excellent sewability on all machine types - lockstitch, chainstitch, overedge and flatlock. Background of the Invention : Buttons that are attached to clothes such as shirts, blouses and other garments are to be attached effectively to a fabric. Currently buttons are attached to shirts chiefly by one of the following two process:- A. Chain stitching B. Lock stitching The chain stitching process which is commonly used to attach buttons to garments produces a very unsatisfactory result because the attached thread is not securely locked with the help of an under thread for a sufficient number of loops. It also leaves exposed thread ends which if pulled can cause the stitch to unravel and the button is detached. Even in lock stitching operation where the under thread is to some extent locked, button security after usage is unsatisfactory. After repeated use and washing of the garment the under thread can be frayed/ separated because the button is detached. There Is hence a clear need for a stitching thread which could retain the essential requirements of a stitching thread like: A. Good sewability with appropriate lubrication and low friction. B. Desired with matching colour accept tolerance levels and C. Lend itself to being wound on a appropriate package with good off winding characteristics on the sewing machines. It also has to acquire radically enhanced locking strength by a suitable method to ensure that a button does not get detached from the garment even when subjected to condition of stress. Prior Art For attaching buttons with the garTnent, it is conventional to pass thread through the holes of the button from the gannent several times. It can be done by conventional sewing technology like chain stitch which was employed for a long period. An essential quality feature of textile stiched connection resides in way the sewing thread material is locked in the material of the sewable area structure to be attached by means of the stitched connection. The chain stitch operation leaves the loose end unsecured and it unravels and releases the button from the attached gamient after repeated washings. This problem has been faced by the users worldwide and the only option available to them was to hand stitch a new button using normal stitching thread. Later on, the sewing machine manufacturers improved the process by introducing lock stitch button sewing machines. The lock stitch button sewing machine uses a needle thread and a lope thread which secures firmly the stitch at the center of the seam hole based on the elasticity of the thread. Lock stitch sewing machine introduction was a recent phenomenon and customers who have already invested in chain stitch machines were hesitant to switch over to lock stitch machines since the cost of lock stitch machine is highly prohibitive. Although the loose end unravelling was minimized in lock stitch machines, after repeated washings, the thread is likely to get loosened out. Patent No. DE 4223853 Gred et. al. teaches a sewing thread suitable for producing chain stiches preferably for sewing on buttons. The sewing thread as it is on Its outer surface has on its outer surface atleast coated a precursor material which gives to a stitched thread increased adherence to the material. The invention thus resides in giving better strength to a thread by coating it with a precursor. US Pat 5869182 teaches a sewing thread wherein a precursor material Is impregnated atleast partways into said thread imparting into the thread Increased adherence due to their outer diameter of the sewing thread by activating a property of the precursor material which increases the actual volume. The emphasis of the invention is to Increase the diameter of the sewing thread in the range of 22 to 100%. (DE 2843589_A1) teaches a method for fixing buttons to articles of clothing wherein the stem of the mechanically sewn button is wrapped under tension with a thread, whose coil is made to swell by adding a solvent and after the evaporation of the later, is bonded accompanied by contraction, so that the button stem is firmly surrounded by a homogeneous sleeve. The winding thread is constituted by cellulose acetate yams, which are wetted and bonded with acetone. However, although this known method leads to the stiff, durable and knot-free button stem, the application of the solvent involves an additional working step and the evaporation of the solvent is prejudicial to the health of the operators. DE-A-40 25 291, discloses a method for producing water or moisture proof stiched connections In sewing woven synthetic or rubber materials, or woven materials coated with synthetic or rubber, or multilayer synthetic or rubber materials, which In a given case are reinforced with metal foil, by inserting a body core of synthetic or rubber foil between the parts to be sewn upon sewing and by causing the sealant emanating from the pierced body core to cross link. In particular, organo-polysiloxane masses are used as sealants. The above method has a disadvantage that the the precision of the stitched connection over longer sewing periods, and on the other hand results in residues of sealant material on the needle which, upon continued sewing may cause damage inside the fabric and/or to the needle, or even to the sewing device. Consequently there is a need to particularly furnish a sewing thread which can lock the sewing thread with the garment when used with any stiching. The object of the present invention The object of the invention is to develop a self locking sewing thread having enhanced button security when stiched to clothes. The developed Impregnated thread has a pull through resistance of formed seams to about 30 pounds and when lubricated with a silicon emulsion of high viscosity of about 8000 centistorks to 10,000 centistokes coupled with emulsifiers and waxes, provides a self adhesive preparation when subjected to heat treatment. The object of the present invention is to provide a simple solution for impreagnating the thread, which upon activation of normal heating element like steam iron or electric iron, activates the coated adhesive to the base garment and effects tight security for the buttons. Another object of the invention is to provide a stiching thread which is unaffected by majority of mineral and organic acids, has good resistance to weak alkalis, and morderate resistance to strong alkalis. Another object of the invention is to provide a stiching thread which is unaffected by majority of mineral and organic acids, has good resistance to weak alkalis, and morderate resistance to strong alkalis. It is a further object of the present invention to provide a thread having high strength unaffected by finishing additives, free of toxic substances and is harmless to the human skin, excellent durability, low moisture regain and low shrinkage. Accordingly the present invention relates to a shelf locking sewing thread having an enhanced button security when stiched to clothes comprising a poly thread impreagnated with a metered fusible compound as herein described of tow transistion temperature, mixed with a solvent, stretched and dry heated in three chamber compartment zone maintained at three different temperatures as herein described to attain a pull through resistance of formed seams of 30 pounds, lubricated with a silicon emulsion of high viscosity of 8000 centistorkes to 10,000 centistorkes coupled with emulsifiers and waxes providing a self adhesive property to the said thread when subjected it to a low heat. The said thread is preparad by a process comprising the steps of: a) 100 gms of copolyamide and/or copolyester is mixed with I litre of isopropyl alcohol to prepare a fusion solution; b) stirring and heating the said solution at 70-90" C to obtain a homogenous solution ," c) cooling the said solution to 40-45" C, to obtain fusible impregnated solution; d) passing the thread through the said fusible solution kept in a trough maintained at a temperature of 40-45" C to keep the homogenity and prevent coagulation; e. streching the said dried coated thread at a tension of 2% to 5% between the input and output rollers at a speed of 20m/minute to 50 m/minute to attain a pull through resistance of 30 pounds giving dimensional stability to the dried structure; f . passing the said stretched thread through the porcelain eyelet, separator, pressure roller and guide rollers; g. lubricating the coated thread with silica emulsion coupled with emulsifiers and waxes; h . collecting the said stretched thread on metal bobbin ; ). steam activating the said stretched thread to obtain a self locking thread. The above process of self locking thread is carried out in an apparatus comprising ; -a vessel for preparing a fusion solution of copolyamide and copolymer powder in a solvent; -means for stirring and heating the solution to obtain a fusible solution; - means for passing the thread through the fusible solution; -means for drying the said coated thread in a controlled manner; -means for passing thread at the desired speed, pressure and temperautre to obtain a thread having a pull through resistance of formed seams 30 pounds ; -means for activating the thread to impart the characteristic of self locking. The said apparatus for producing comprises a means for passing the thread though the fusible coat mix, are feeding creel guided through porcelain eyelet, tension rod, fusion solution trough, guide roller and separator. The said appatatus for producing self locking thread also comprises means for drying the coated thread is a horizontal chamber having three compartmants maintained at a temperature of 110 to 130- C by infra red radiation, means for pasing the thread at a speed of 20m/minute to 50 m/minute are the proceline eylet, separator, pressure roller and guide rollers, aranged in series, means to collect the thread are metal bobbin fitted in the take up creel via "U" type procelain guide, means for activating the thread is a steam iron to impart self locking characteristic. Brief Description of the Accompanying Drawings Fig. 1 shows a longitudinal sectional view of the apparatus for implementing the method according to the invention. Fig. 2 a shows the process diagram of the coated thread . Fig. 2 b shows the process diagram of the coated thread. Fig. 2 c shows the process diagram of the coated thread. Description of the Invention In the ready made garments industry, normal stitching thread made out of cotton or spun polyester is used for button stitching. Various trials were conducted by coating polymeric adhesives and copolyester esters with soft cotton threads, mercerized cotton threads and high tenacity staple spun polyester threads. However the adhesion and subsequent activation of the coated adhesive were not satisfactory for the intended end use. The thread employed were 118 detect X 3 Mercerised Cotton, 147 dtex X 2 Soft Cotton, 98 dtex X 3 Staple Spun Polyester, 83 dtex X 3 Staple Spun Polyester and 205 dtex X 2 Polyester Cotton Corespun and 205 dtex X 3 Polyester Cotton Corespun. The dyed thread of the above constructions were subjected to the following techniques:- fvlethod A: Application of Low Density Poly Ethylene (LDPE) and High Density Poly Ethylene (HDPE) dissolved In suitable solvent in a high temperature, high pressure package dyeing machine by exhaust. Method B: Application of LOPE, HOPE and esterified copolyamides in a lick roller method with reduced speed of winding. The lick roller rotates in the opposite direction to that of thread off take and the liquor level was adjusted periodically by replenishing fresh material. Method C: Application of LDPE, HDPE and esterified copolyamides in a coating machine having pre application bath and subsequent drying using steam heated rollers. Method D: Application of the above adhesive solutions in a modified coating machine with pre application bath and subsequent drying using radiation heating. In method A, coated stitching thread exhibited very high patchiness and unlevel due to uneven uptake of the chemical during in-out and out-in operation of the package dyeing machine, the coating was not uniform and the inside layers were not coated. In some length of the thread, heavy accumulation of adhesive solution was observed. In method B, the uptake was too high and there was a considerable increase in thread diameter. The thread did not perform well during subsequent heat activation process using steam iron. In method C, the thread was exhibiting high wet strength and prolonged exposure of adhesive coated wet conditions, provided opportunity for growth of fungus and bacteria. Insufficient drying time and temperature of steam heated rollers resulted in poor adhesion behavior. In method D, a fairly uniform dried material was obtained. However the problem of patchiness of adhesive coated material was observed and it was minimised using low concentrations. To achieve the optimum strength/fitness ratio of continuous filament threads together with the sewing performance and surface characterstics of spun fibre threads polyester filament yarns covered and protected by polyester cotton fibres (poly/poly) are used for the said invention. The stitching thread is impregnated and surface coated by a specially engineered fusible compound which is applied under chosen condition of stretch, humidity and temperature which can be subsequently thennally activated to impart self locking characteristics to the thread. ,vA The thread is subjected to a chemical treatment in a bonding machine (60 Q ends machine) for coating. The thread from the feeding creel (1) is guided (2) jhthe procefin eyelet (4) to the applicator (6) where fusion solution through (1^) is stored and applied, the tension rod (III), guide rollex (7) and ^ {—'Ui separator (10). The Fusion Solution is made frortf'Grlltex (^^olyamide..^^ v-^Ji-xr and/or copolyester powder) dissolved in 1 litre of solvenT. the solvent can "{ ^^^^t A , (,1^ /be Mercaptal, Isopropyl alcohol or Toluene. This mixture is heated at a . v^ ^ temperature of about 70 to 90° C with continuous stirring to get a t homogenous solution called 10% mix. This solution is kept in 40-45° C. The thread is passed through this solution which is kept in trough at a maintained temperature of 40-45°C by to prevent coagulation. This sojution is called fusible coat mix. Thread is then dried by passing through the horizontal heating chamber (VII) in a chamber having 3 compartments kept at a temperature of 110 to 130 ° C by infra red radiation. Streched thread at a tension of about 2% to 5% is passed through this chamber for uniform homogenous coating at a speed of about 20 m/minute to 50 m/minute and again taken out through the porcelin eyelet (4), separator (10), pressure rollers (14) three in number, guide roller (7). Then lubrication/finishing is done to Improve the frictional properties of the thread during actual sewing. The lubrication mixture consist of high viscous silicon of 5000 centistokes coupled with emulslfiers and waxes, which upon application improves the stick slick properties of the thread. The coated thread Is finally collected in the metal bobbins (15) fited in the take up creel (18) via "U" type porcelain guide (15). The thread is used with a subsequent heat activation process using steam iron for setf locking characteristice of the thread. We claim : 1. A process for the production of a self locking sewing thread comprising the following steps: a) taking 100 gms of copolyamlde and/or copolyester and mixing it with 1 litre of isopropyl alcohol to prepare a fusion solution; b) stirring and heating the said solution at 70-90° C to obtain a homogenous solution ; c) cooling the said solution to 40-45° C, to obtain fusible impregnated solution and storing the said fusible solution in a trough; d) passing the poly thread by conventional means through the said fusible solution kept in a said trough maintained at a temperature of 40-45°C to keep the homogenity and prevent coagulation; e) squeezing out the extra chemical coated on the thread by passing the said coated thread through tension rollers and felt pad; f) drying the said impregnated thread by passing through the individual ceramic eyelets to avoid ends getting entangled to a vertical three chambered compartment, maintained at a temperature of 110 to 130" C by infra red radiation; g) stretching the said dried coated thread at a tension of 2% to 5% between the input and output rollers at a speed of 20m/minute to 50 m/minute to attain a pull through resistance of 30 pounds giving dimensional stability to the dried structure; h) passing the said stretched thread through the porcelain eyelet, separator, pressure roller and guide rollers; i) lubricating the coated thread with silica emulsion coupled with emulsifiers and waxes; j) collecting the said stretched thread on metal bobbin ; k) steam activating the said stretched thread to obtain a self locking thread. 2. A self locking sewing thread as obtained by the process claimed in claim 1, having an enhanced button security when stitched to clothes. 3. A process for producing self locking thread as hereinbefore described with reference to the accompanying drawings. I

Documents:

0967-mas-2002 abstract-duplicate.pdf

0967-mas-2002 abstract.pdf

0967-mas-2002 claims-duplicate.pdf

0967-mas-2002 claims.pdf

0967-mas-2002 correspondence-others.pdf

0967-mas-2002 correspondence-po.pdf

0967-mas-2002 description (complete)-duplicate.pdf

0967-mas-2002 description (complete).pdf

0967-mas-2002 drawings-duplicate.pdf

0967-mas-2002 drawings.pdf

0967-mas-2002 form-1.pdf

0967-mas-2002 form-19.pdf

0967-mas-2002 form-26.pdf

0967-mas-2002 form-3.pdf